Chimney Condensation In Attic

The new decking was mostly dry except for droplets of moisture apparently condensate not leakage from the roof on a few nails.

Chimney condensation in attic.

When a fire is started the new warm air moving into the chimney comes into contact with the cold chimney walls causing condensation. The pattern of wetness is relatively uniform on all the sides of the chimney exposed in the attic. The wetness is more severe at the basement and or the first floor than the second floor or the roof. In some cases the heat from the fire will cause the condensate to evaporate.

It has happened and usually isn t discovered until people have spent a terrible sum fixing everything else. Condensation of exhaust gases are evidenced or accompanied by one or more of the following. The walls of the chimney can take time to warm up so when a new fire is lit the hot exhaust air from the fire will come into contact with the cold walls of the chimney and condensation will occur. Signs of chimney damp the signs of chimney damp can be similar to the signs of regular damp except they all occur around your fireplace or chimney.

There may be damp patches on the chimney breast or the ceiling above it or possibly the walls around it. A flue that is too large allows too much air to circulate making it difficult for the warm gas and vapors exiting the furnace to create a strong updraft up and out of the vent. Normal amounts of humidity and moisture in the hot air condense inside your chimney as the air cools leaving water which can be as acidic as bleach. In the attic a kneewall blocked observation of the chimney.

Condensation can also occur within the chimney. In early january we cut an access to observe the chimney and the underside of the roof deck. Over time this acidic moisture can do serious damage to your chimney and masonry work but that s not the worst of it. You might also see staining or discolouration in these areas.